Kenyan vender sells American and Kenyan flags, in Nairobi, Kenya Friday, July 24, 2015. In his first trip to Kenya since he was a U.S. senator in 2006, Obama is scheduled to arrive in Kenya on Friday, the first stop on his two-nation African tour in which he will also visit Ethiopia. (AP Photo/Khalil Senosi)

                    

A Kenyan vender sells American and Kenyan flags, in Nairobi, Kenya Friday, July 24, 2015. In his first trip to Kenya since he was a U.S. senator in 2006, Obama is scheduled to arrive in Kenya on Friday, the first stop on his two-nation African tour in which he will also visit Ethiopia. (AP Photo/Khalil Senosi)